First off, you shouldn't need the conversion kit. If you had the auto hubs with 6 bolts in them, then you do not need a conversion kit. Hold onto it so you can take it back.
A few tips...
1. Take out everything clear down to the nuts that hold the wheel bearing in place. Then, put the washer back in that goes on this side of those nuts. Make sense?
2. Before you install the hubs, spray a coating of spray lubricant on the new hubs and the splines inside the hubs (part where the new hub is going). If you use grease, there won't be enough room to lock or unlock the hubs. If you don't use anything, they can be a booger to turn. Some people use WD-40, I recommend spray silicone. Makes locking and unlocking much easier and helps repel water.
3. Before putting the final outer locking ring in place, bend the end of it in slightly. This makes it much easier to get out of the groove later. This should make sense when you get that far.
All in all it should take you less than 10 minutes per hub.